Square retail display unit



FIG. 1 is a general perspective view of the square retail display unit embodying the present invention;

FIG. 2 is a front elevation of the square retail display unit shown in FIG. 1, with the back and both sides presenting identical views; and,

FIG. 3 is a top plan view of the square retail display unit shown in FIG. 1.

The bottom of the square retail display unit forms no part of the claimed design. 

The ornamental design for a square retail display unit, as shown and described. 